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Recursive Queries

A host within a specified domain (eg a machine at Bendigo, in domain bendigo.latrobe.edu.au) is configured to "know" the IP address of its local nameserver. What happens when it sends a query for a non-local name, (eg amazon.com)? The sequence of events is something like: It's obvious that recursive queries could be quite slow. The DNS provides a way of "short-circuiting" the whole process. If (for example) the local nameserver already knows (due to caching) the IP address of a nameserver for the .com domain in the above example, it can contact it directly, thus avoiding many recursive stages. This is called an iterative query. In practice, most (all?) queries to root nameservers are iterative. Every nameserver is configured to know the IP address of at least one root nameserver.
 


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